Method of making a cylindrical brush

ABSTRACT

A woven cut pile brush whose pile tufts are formed from glass fibers is particularly well suited for cleaning toner particles from reusable electrostatic imaging surfaces in xerographic processes. In addition, the backing yarn of the woven pile fabric from which the brush is made, is thermoplastic. A cylindrical brush is formed by helically winding a strip of the pile fabric on a mandrel, and heating the backing yarn to fuse the abutting edges of adjacent convolutions of the fabric together and to lock the pile tufts in place in the backing fabric.

United States Patent [7 2] Inventor Thomas W. Solarek Fairport, N.Y. [21] Appl. No. 889,282 [22] Filed Dec. 30, 1969 [45] Patented Oct. 5, 1971 [73] Assignee Xerox Corporation Rochester, N.Y.

[54] METHOD OF MAKING A CYLINDRICAL BRUSH 4 Claims, 4 Drawing Figs. [52] US. Cl. 300/21, 35 5/ 1 5 [51] Int. Cl A46d 9/00 [50] Field ofSearch 355/15; 118/637; 15/1.5; 300/21 [56] References Cited UNITED STATES PATENTS 2,621,507 1271952 Pharris et a1 300/21 X 2,789,075 4/1957 Stahl 300/21 X 3,107,382 10/1963 Tilgner Primary Examiner-Granville Y. Custer, Jr. AttorneysPaul M, Enlow, James J. Ralabate, Albert A.

Mahassel, Peter H. Kondo and Boris Haskell PATENTED 0m 5 Ian m vm'mic. THOMAS W. SOLAREK A TTORWEY I 1 METHOD OF MAKING A CYLINDRICAL BRUSH BACKGROUND OF INVENTION In xerography and related arts, a latent electrostatic information image is formed on an electrically insulating carrier. This latent image is developed into a visible image by the application of toner particles to the carrier surface, whereby the particles are caused to adhere electrostatically either to the portions of the carrier surface that are electrostatically charged or to the portions that are not charged, and the adhered toner particles may then be transferred imagewise to an image receiving or record sheet. After the transfer, the insulating carrier is cleaned of residual toner particles and freed of the image charge pattern, and then reused in the production of another image.

Effective and efficient cleaning of the residual toner particles' from the insulating carrier is a critical operation, since any residual toner will interfere with a subsequent image developed on the carrier. At the same time, it is important that the cleaning operation not damage the image carrier surface, and this is a particularly sensitive problem when the carrier is a reusable selenium photoconductor, as is often used to convert optical images to electrostatic images. Cylindricalor belt-type brushes are commonly used in this cleaning operation.

SUMMARY OF mar INVENTION The present invention relates to an improvement in brushes used for cleaning residual toner material from xerographic electrostatic image carriers, and to a method of making such brushes in cylindrical form.

In accordance with the present invention, the brush is formed from a woven cut pile fabric, wherein the pile tufts are formed from glass fibers of very fine diameter. The woven cut pilet'orm of pile fabric provides a very uniform pile height, and a fine glass fiber pile enables a very dense array of fiber ends. These two features combine to afford an effective brushing action over the carrier surface for efficient removal of the residual toner material therefrom. In addition, these fibers do not abrade or otherwise mar the insulating electrostatic image carrier surfaces usually employed in a xerographic apparatus.

Further, the backing fabric of the woven pile material may be formed from yarns that are composed either entirely or partially of thermoplastic fibers, and this feature enables the practice of a particularly efl'icient method of fabricating the brush. In the fabrication method of the present invention, a strip of the woven cut pile material is helically wound on a cylindrical mandrel, with the adjacent edges of successive convolutions in abutting relation. Heating the base fabric or backing to the fusion point of its thermoplastic fibers causes the edges of successive convolutions to fuse together, forming an integral brush; and if desired, the mandrel may be selected from materials to which the fused thermoplastic material will adhere, so as to laminate the brush fabric to a structurally rigid core in this single forming operation. An additional advantage obtained in this process, is that fusion of the thermoplastic base fabric fibers locks the cut pile fibers in place, without the necessity of applying a separate adhesive to the under surface of the backing fabric.

It is therefore one object of the present invention to provide an improved brush for cleaning toner material from the electrostatic image carrier of a xerographic apparatus.

Another object of the present invention is to provide such a brush formed from a woven cut pile material.

Another object of the present invention is to provide such a brush wherein the pile is formed from glass fibers.

A further object of the present invention is to provide a method of forming a brush from a woven pile material.

And still another object of the present invention is to provide such a method wherein the brush is formed from helical convolutions of the woven pile material, by fusion of thermoplastic fibers in the backing fabric of the pile material. I

Other objects and advantages of the present invention will become apparent to those skilled in the art, from a consideration of the following detailed description of exemplary embodiments of the invention had in conjunction with the accompanying drawings.

DESCRIPTION OF DRAWINGS FIG. 1 is a schematic illustration of a conventional xerographic photocopying apparatus;

FIG. 2 is a partial and enlarged perspective view of a brush used for cleaning residual toner particles from the electrostatic imaging surface of the apparatus of FIG. 1;

FIG. 3 is an enlarged fragmentary cross-sectional view of the pile fabric used in making the brush of FIG. 2; and

FIG. 4 illustrates a stage in the manufacture of said brush.

DETAILED DESCRIPTION FIG. 1 schematically illustrates a well-known xerographic process and apparatus for electrostatically photocopying documents. Drum 10 is provided with permanent photoconductive layer 11 over its cylindrical surface. The photoconductive layer 11 is commonly formed of selenium, and presents a relatively low electrical resistance when illuminated with light and a relatively high resistance whennot illuminated. A plurality of operational stations are positioned about the periphery of the drum as follows: an optical station is provided at 14, for focusing an optical image on the photoconductor, a developing station is provided at 19, an image transfer station is provided at 24, a drum-cleaning station is located at 30, a general illuminating station is located at 31, and it is followed by a general charging station at 32.

Assuming that the drum 10 is rotating in the direction of arrow A, and assuming that the'drum surface is clean and uniformly charged with an electrostatic surface charge as it approaches station 14, an image of a portion of document 13 is focused by optical system 12 on the photoconductor surface 11 at station 14. As the drum advances in the direction of arrow A, successive portions of the document 13 are focused on successive portions of the photoconductor 11. The portions of photoconductor 11 that are illuminated with light become conductive during the illumination period, causing a discharge to ground of the corresponding electrostatic charge portion on the surface of the photoconductor, and resulting in a latent electrostatic image of document 13 on the surface 0 drum 10.

The electrostatic latent image is advanced to the developing station 19, where a housing 15 contains a charge of electroscopic toner particles 18, and a roll 16 having a pile brush 17 on its surface. As roll. 16 rotates, the pile brush 17 passes through the toner particles and then across the surface of drum l0, distributing the toner particles over the surface of the drum. The toner particles adhere to the drum in areas containing a residual charge, but not in the uncharged areas, resulting in development to visual form of the latent electrostatic image corresponding to document 13.

At station 24, this image is transferred to image-receiving web 20. Web 20 is drawn from supply roll 21 and is guided in contact with drum 10 for a short distance by guide rolls 22 and 23. Transfer of the toner particles constituting the developed image may be aided by an appropriate electrical field or by charging of the web 20 by corona-charging electrode 20, as is well understood in the art. After the image is transferred to the web 20, the web may be passed through a heater 25 to fuse the toner particles to the web, and the web is guided by roll 26 to a delivery station.

After the image transfer operation, residual toner particles are removed from the surface of drum 10 by brush 27 at station 30. Then the photoconductive surface 1 l is exposed at 31 to uniform illumination by lamp 28. to erase any residual electrostatic image. Before returning to the optical exposure station, the surface of the photoconductor is exposed to a general corona discharge by electrode 29 at station 32, to provide a unifonn electrostatic charge over the photoconductive surface 11 and thereby enable electrostatic optical recording of an image of the document 13. Brush 27, for cleaning residual toner particles from the selenium surface 11 of drum 10, is shown in the partial and enlarged perspective view of FIG. 2. As there shown, the brush comprises a cylindrical structurally rigid core 41, preferably formed of a suitable metal or other rigid material, such as a phenolic resin and glass fiber laminate. A woven cut pile fabric 42 is secured over the cylindrical surface of the core 41, this fabric comprising a woven backing 43 carrying the pile fibers 44 interwoven therewith. As shown in FIG. 3, the woven backing 43 comprises warp and woof yarns 45 and 46, and woven into the backing is the pile yarn 47. When the pile yarn is cut, the fibers at the cut ends of the yarn disperse to form the tufts 48, with the fiber ends all at substantially the same height. In accordance with the present invention, the pile yarn 47 is formed from very fine glass filaments, and backing yams 45 and 46 are formed from thermoplastic resin filaments, such as polyethylene, polypropylene, nylon plastic, etc.

Manufacture of brush 27 is illustrated by FIG. 4. Using the brush core 41 as a mandrel, a strip of the cut woven pile fabric 42 is helically wound thereon with the adjacent ends of successive convolutions abutting, as shown at 51, employing conventional and well known techniques and apparatus. The ends of the wound helix are, of course, squared by trimming, and these ends may be secured to the core mandrel 41 by an adhesive or by clamps to retain the helix on the mandrel. An electric heater 52 is then inserted in the hollow center of the core 41, for the period of time and at the temperature required to effect partial fusing of the backing yarns 45 and 46 of the fabric 42. As a result of this fusion, successive convolutions of the helically wound fabric 42 are united along the abutting edges 51, and the entire backing surface may be bonded to the core 41. Also, it is apparent that the partial fusion locks the cut pile yarn segments 47 in place in the backing of the fabric.

The brush thus fonned corresponds to the cylindrical brush 27, shown in perspective in FIG. 2 and in use in FIG. 1. Obviously, the brush formed by this method may have various transverse shapes other than the circular shape shown, such as rectangular, semicircular or oval. All transverse shapes, regular or irregular are contemplated as embraced by the term cylindrical as used herein.

To illustrate the present invention more specifically, it is preferred that the glass fiber yarns 47 used to form the pile tufts 48, be formed from glass filaments having a diameter between about 3 microns and about l0 microns, and preferably about 4 microns, with between about and 450 filaments per yarn. Further, this pile fiber yarn should be woven into the fabric at a spacing that provides between I and 2 million, and preferably about 1% million pile fiber ends per square inch of pile fabric. The pile height should be between about 0.4 and 0.8 inch, and preferably about 0.6 inch. A preferred backing yarn is polypropylene, but it will be apparent that the specific composition and diameter of the backing yarns are not at all critical to the practice of the present invention.

Having thus described a specific embodiment of the present invention, it is understood that the scope of the invention is not limited to the details of the foregoing description, and numerous modifications and variations will be apparent to those skilled in the art. Such variations and modifications as are embraced by the spirit and scope of the appended claims, are contemplated as being within the purview of the present invention.

What is claimed is:

l. A method of forming a cylindrical brush from pile fabric whose backing yarns include thermoplastic fibers, comprising winding a strip of said fabric over a cylindrical mandrel with the adjacent edges of successive convolutions in abutting relationship, and heating the backing yarns to a state of partial fusion, whereby said abutting edges are fused together and the pile yarn seglrlnents are locked in the fused backing yarns.

2. A met od as set forth in claim 1, wherein said thermoplastic fibers fuse to said mandrel, whereby said mandrel becomes the core of said brush.

3. A method as set forth in claim 1, wherein the pile yarn of said fabric is formed from glass fibers.

4. A method as set forth in claim 3, wherein said backing yarns include fibers selected from the group of thermoplastic materials consisting of polyethylene, polypropylene, and nylon plastic. 

1. A method of forming a cylindrical brush from pile fabric whose backing yarns include thermoplastic fibers, comprising winding a strip of said fabric over a cylindrical mandrel with the adjacent edges of successive convolutions in abutting relationship, and heating the backing yarns to a state of partial fusion, whereby said abutting edges are fused together and the pile yarn segments are locked in the fused backing yarns.
 2. A method as set forth in claim 1, wherein said thermoplastic fibers fuse to said mandrel, whereby said mandrel becomes the core of said brush.
 3. A method as set forth in claim 1, wherein the pile yarn of said fabric is formed from glass fibers.
 4. A method as set forth in claim 3, wherein said backing yarns include fibers selected from the group of thermoplastic materials consisting of polyethylene, polypropylene, and nylon plastic. 